Alkylene oxide adducts of aliphatic amine compounds are important compounds in the field of products for household and industrial uses. In particular, they are used as starting materials for surfactants, intermediates for fiber treatments and for bactericidal substances, and components of insecticides and of fiber softeners. In these applications, the adducts desirably are pure and colorless substances.
Such alkylene oxide adducts of aliphatic amine compounds are obtained from aliphatic amine compounds, as starting materials, derived from animal fats such as beef tallow, vegetable oils such as coconut oil and palm oil, and the like by causing these aliphatic amine compounds to add an alkylene oxide. However, the alkylene oxide adducts obtained from such aliphatic amines derived from animal fats, vegetable oils, and the like have problems, for example, that generally they are colored or are turbid and they deteriorate in color through long-term storage to give products which are poor in appearance.
Since such colored or turbid alkylene oxide adducts arouse troubles when used in such applications as the aforementioned ones, methods for obtaining alkylene oxide adducts having an excellent color have conventionally been proposed. For example, a method in which an acid treatment is conducted when an alkylene oxide is added to an aliphatic amine (specification of U.S. Pat. No. 2,422,503), a method in which an alkali metal salt of boron hydride is added (specification of U.S. Pat. No. 3,207,790), and a method in which a reaction is conducted at a low temperature (JP-B 51-40052 corresponding to U.S. Pat. No. 3,585,239) are disclosed. Other techniques which have been disclosed include a method in which an alkylene oxide is added to an aliphatic amine and the resultant adduct is aged at 180 to 280.degree. C. for 1 to 20 hours (JP-A 54-24807).
However, these methods have drawbacks, for example, that the operation is complicated or a fully excellent color and transparency cannot be obtained.